When I set up a "shortcut" for a host in ~/.ssh/config, e.g. (with a valid
HostName of course)
"""
Host foo
    User me
    HostName host.remote.com
"""
then open Dolphin and try to open the URL
sftp://foo

I get the error message
"Failed to resolve hostname foo (Name or service not known)".

This happens with the current Tumbleweed (I also tried with the Live CD from
12.11.2017 to make sure I didn't break it accidentally on my system). This has
been broken at least since spring 2017 (don't know when exactly).

Versions of KDE components:
KDE Frameworks 5.39.0
Plasma 5.11.2
Applications 17.08.2

I tried with KDE Neon with the same Frameworks/Plasma/Applications versions and
it works. Therefore I think that the problem is related to Tumbleweed, not to
KDE itself.

Note that using the fully qualified hostname (circumventing .ssh/config) works,
e.g. sftp://me@host.remote.com, but this is not a solution, especially if you
want to use jump hosts (via ProxyCommand or ProxyJump).